CVE-2024-0760

A malicious client can send many DNS messages over TCP, potentially causing the server to become unstable while the attack is in progress. The server may recover after the attack ceases. Use of ACLs will not mitigate the attack. This issue affects BIND 9 versions 9.18.1 through 9.18.27, 9.19.0 through 9.19.24, and 9.18.11-S1 through 9.18.27-S1.

Berkeley Internet Name Domain (BIND) is an implementation of the Domain Name System (DNS) protocols and provides an openly redistributable reference implementation of the major components of the Domain Name System. This package includes the components to operate a DNS server.

Security Fix(es):

The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC responses in a random subdomain attack, aka the "NSEC3" issue. The RFC 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations.(CVE-2023-50868)

A malicious client can send many DNS messages over TCP, potentially causing the server to become unstable while the attack is in progress. The server may recover after the attack ceases. Use of ACLs will not mitigate the attack. This issue affects BIND 9 versions 9.18.1 through 9.18.27, 9.19.0 through 9.19.24, and 9.18.11-S1 through 9.18.27-S1.(CVE-2024-0760)

Berkeley Internet Name Domain (BIND) is an implementation of the Domain Name System (DNS) protocols and provides an openly redistributable reference implementation of the major components of the Domain Name System. This package includes the components to operate a DNS server.

Security Fix(es):

The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC responses in a random subdomain attack, aka the "NSEC3" issue. The RFC 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations.(CVE-2023-50868)

A malicious client can send many DNS messages over TCP, potentially causing the server to become unstable while the attack is in progress. The server may recover after the attack ceases. Use of ACLs will not mitigate the attack. This issue affects BIND 9 versions 9.18.1 through 9.18.27, 9.19.0 through 9.19.24, and 9.18.11-S1 through 9.18.27-S1.(CVE-2024-0760)

Berkeley Internet Name Domain (BIND) is an implementation of the Domain Name System (DNS) protocols and provides an openly redistributable reference implementation of the major components of the Domain Name System. This package includes the components to operate a DNS server.

Security Fix(es):

A malicious client can send many DNS messages over TCP, potentially causing the server to become unstable while the attack is in progress. The server may recover after the attack ceases. Use of ACLs will not mitigate the attack. This issue affects BIND 9 versions 9.18.1 through 9.18.27, 9.19.0 through 9.19.24, and 9.18.11-S1 through 9.18.27-S1.(CVE-2024-0760)

Berkeley Internet Name Domain (BIND) is an implementation of the Domain Name System (DNS) protocols and provides an openly redistributable reference implementation of the major components of the Domain Name System. This package includes the components to operate a DNS server.

Security Fix(es):

A malicious client can send many DNS messages over TCP, potentially causing the server to become unstable while the attack is in progress. The server may recover after the attack ceases. Use of ACLs will not mitigate the attack. This issue affects BIND 9 versions 9.18.1 through 9.18.27, 9.19.0 through 9.19.24, and 9.18.11-S1 through 9.18.27-S1.(CVE-2024-0760)

A malicious client can send many DNS messages over TCP, potentially causing the server to become unstable while the attack is in progress. The server may recover after the attack ceases. Use of ACLs will not mitigate the attack. This issue affects BIND 9 versions 9.18.1 through 9.18.27, 9.19.0 through 9.19.24, and 9.18.11-S1 through 9.18.27-S1.

A malicious client can send many DNS messages over TCP, potentially causing the server to become unstable while the attack is in progress. The server may recover after the attack ceases. Use of ACLs will not mitigate the attack. This issue affects BIND 9 versions 9.18.1 through 9.18.27, 9.19.0 through 9.19.24, and 9.18.11-S1 through 9.18.27-S1.

A malicious client can send many DNS messages over TCP, potentially causing the server to become unstable while the attack is in progress. The server may recover after the attack ceases. Use of ACLs will not mitigate the attack. (CVE-2024-0760) Resolver caches and authoritative zone databases that hold significant numbers of RRs for the same hostname (of any RTYPE) can suffer from degraded performance as content is being added or updated, and also when handling client queries for this name. (CVE-2024-1737) If a server hosts a zone containing a "KEY" Resource Record, or a resolver DNSSEC-validates a "KEY" Resource Record from a DNSSEC-signed domain in cache, a client can exhaust resolver CPU resources by sending a stream of SIG(0) signed requests. (CVE-2024-1975) Client queries that trigger serving stale data and that also require lookups in local authoritative zone data may result in an assertion failure. (CVE-2024-4076)

These are all security issues fixed in the bind-9.20.0-1.1 package on the GA media of openSUSE Tumbleweed.

This update for bind fixes the following issues:

Update to release 9.18.28

Security fixes:

• CVE-2024-0760: Fixed a flood of DNS messages over TCP may make the server unstable (bsc#1228255)
• CVE-2024-1737: Fixed BIND's database will be slow if a very large number of RRs exist at the same name (bsc#1228256)
• CVE-2024-1975: Fixed SIG(0) can be used to exhaust CPU resources (bsc#1228257)
• CVE-2024-4076: Fixed assertion failure when serving both stale cache data and authoritative zone content (bsc#1228258)

Changelog:

• Command-line options for IPv4-only (named -4) and IPv6-only (named -6) modes are now respected for zone primaries, also-notify, and parental-agents.
• An RPZ response’s SOA record TTL was set to 1 instead of the SOA TTL, if add-soa was used. This has been fixed.
• When a query related to zone maintenance (NOTIFY, SOA) timed out close to a view shutdown (triggered e.g. by rndc reload), named could crash with an assertion failure. This has been fixed.
• The statistics channel counters that indicated the number of currently connected TCP IPv4/IPv6 clients were not properly adjusted in certain failure scenarios. This has been fixed.
• Some servers that could not be reached due to EHOSTDOWN or ENETDOWN conditions were incorrectly prioritized during server selection. These are now properly handled as unreachable.
• On some systems the libuv call may return an error code when sending a TCP reset for a connection, which triggers an assertion failure in named. This error condition is now dealt with in a more graceful manner, by logging the incident and shutting down the connection.
• Changes to listen-on statements were ignored on reconfiguration unless the port or interface address was changed, making it impossible to change a related listener transport type. That issue has been fixed.
• A bug in the keymgr code unintentionally slowed down some DNSSEC key rollovers. This has been fixed.
• Some ISO 8601 durations were accepted erroneously, leading to shorter durations than expected. This has been fixed
• A regression in cache-cleaning code enabled memory use to grow significantly more quickly than before, until the configured max-cache-size limit was reached. This has been fixed.
• Using rndc flush inadvertently caused cache cleaning to become less effective. This could ultimately lead to the configured max-cache-size limit being exceeded and has now been fixed.
• The logic for cleaning up expired cached DNS records was tweaked to be more aggressive. This change helps with enforcing max-cache-ttl and max-ncache-ttl in a timely manner.
• It was possible to trigger a use-after-free assertion when the overmem cache cleaning was initiated. This has been fixed. New Features:
• A new option signatures-jitter has been added to dnssec-policy to allow signature expirations to be spread out over a period of time.
• The statistics channel now includes counters that indicate the number of currently connected TCP IPv4/IPv6 clients.
• Added RESOLVER.ARPA to the built in empty zones. Feature Changes:
• DNSSEC signatures that are not valid because the current time falls outside the signature inception and expiration dates are skipped instead of causing an immediate validation failure. Security Fixes:
• A malicious DNS client that sent many queries over TCP but never read the responses could cause a server to respond slowly or not at all for other clients. This has been fixed. (CVE-2024-0760)
• It is possible to craft excessively large resource records sets, which have the effect of slowing down database processing. This has been addressed by adding a configurable limit to the number of records that can be stored per name and type in a cache or zone database. The default is 100, which can be tuned with the new max-records-per-type…

It was discovered that Bind incorrectly handled a flood of DNS messages over TCP. A remote attacker could possibly use this issue to cause Bind to become unstable, resulting in a denial of service. (CVE-2024-0760)

Toshifumi Sakaguchi discovered that Bind incorrectly handled having a very large number of RRs existing at the same time. A remote attacker could possibly use this issue to cause Bind to consume resources, leading to a denial of service. (CVE-2024-1737)

It was discovered that Bind incorrectly handled a large number of SIG(0) signed requests. A remote attacker could possibly use this issue to cause Bind to consume resources, leading to a denial of service. (CVE-2024-1975)

Daniel Stränger discovered that Bind incorrectly handled serving both stable cache data and authoritative zone content. A remote attacker could possibly use this issue to cause Bind to crash, resulting in a denial of service. (CVE-2024-4076)

On Ubuntu 20.04 LTS, Bind has been updated from 9.16 to 9.18. In addition to security fixes, the updated packages contain bug fixes, new features, and possibly incompatible changes.

Please see the following for more information:

https://kb.isc.org/docs/changes-to-be-aware-of-when-moving-from-bind-916-to-918